3ph0 | pdb_00003ph0

Crystal structure of the heteromolecular chaperone, AscE-AscG, from the type III secretion system in Aeromonas hydrophila

spinqualitylabelsall models 3ph0, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3ph0 is a 4 chain structure with sequence from "aeromonas_liquefaciens"_kluyver_and_van_niel_1936 "aeromonas liquefaciens" kluyver and van niel 1936. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed BACKGROUND: The putative needle complex subunit AscF forms a ternary complex with the chaperones AscE and AscG in the type III secretion system of Aeromonas hydrophila so as to avoid premature assembly. Previously, we demonstrated that the C-terminal region of AscG (residues 62-116) in the hetero-molecular chaperone, AscE-AscG, is disordered and susceptible to limited protease digestion. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report the crystal structure of the ordered AscG(1-61) region in complex with AscE at 2.4 A resolution. Helices alpha2 and alpha3 of AscE in the AscE-AscG(1-61) complex assumes a helix-turn-helix conformation in an anti-parallel fashion similar to that in apo AscE. However, in the presence of AscG, an additional N-terminal helix alpha1 in AscE (residues 4-12) is observed. PscG or YscG in the crystal structures of PscE-PscF-PscG or YscE-YscF-YscG, respectively, assumes a typical tetratricopeptide repeat (TPR) fold with three TPR repeats and one C-terminal capping helix. By comparison, AscG in AscE-AscG(1-61) comprises three anti-parallel helices that resembles the N-terminal TPR repeats in the corresponding region of PscG or YscG in PscE-PscF-PscG or YscE-YscF-YscG. Thermal denaturation of AscE-AscG and AscE-AscG(1-61) complexes demonstrates that the C-terminal disordered region does not contribute to the thermal stability of the overall complex. CONCLUSION/SIGNIFICANCE: The N-terminal region of the AscG in the AscE-AscG complex is ordered and assumes a structure similar to those in the corresponding regions of PscE-PscG-PscF or YscE-YscF-YscG complexes. While the C-terminal region of AscG in the AscE-AscG complex is disordered and will assume its structure only in the presence of the substrate AscF. We hypothesize that AscE act as a chaperone of the chaperone to keep AscG in a stable but partially disordered state for interaction with AscF. Crystal structure of the heteromolecular chaperone, AscE-AscG, from the type III secretion system in Aeromonas hydrophila.,Chatterjee C, Kumar S, Chakraborty S, Tan YW, Leung KY, Sivaraman J, Mok YK PLoS One. 2011 Apr 29;6(4):e19208. PMID:21559439 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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